This invention relates to a process for producing an .alpha.,.beta.-unsaturated carboxylic acid or esters thereof by contacting an .alpha.-hydroxycarboxylic acid amide independently with a solid acid catalyst, or along with water and/or an aliphatic alcohol.
A process for producing the .alpha.,.beta.-unsaturated carboxylic acid esters, for example, methyl methacrylate on a commercial scale, comprises reacting acetone cyanohydrin with concentrated sulfuric acid to form methacrylamide sulfate and thereafter esterifying this with methanol.
This process however has numerous drawbacks including, for example, the corrosion of the apparatus by the concentrated sulfuric acid, the necessity for treating the ammonium sulfate of low value that is produced in large quantities as a by-product, and the need to cope with the pollution that results from the spent sulfuric acid.